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Oral Glucose Tolerance Test

An oral glucose tolerance test measures the body's ability to use glucose, a type of sugar found in fruits and many other foods. (Glucose is the main source of energy used by the body.)

After not eating all night, the person being tested drinks a special sugar solution on the morning of the test. A blood sugar sample is taken from a vein in the person's arm once each hour for several hours to see how much the blood sugar increases and then decreases over time. The test is done in a doctor's office or lab.

The oral glucose tolerance test can be used to diagnose prediabetes and diabetes. It is used to diagnose gestational diabetes, which develops during pregnancy.

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Alan C. Dalkin, MD - Endocrinology
Last Revised July 5, 2011

WebMD Medical Reference from Healthwise

Last Updated: July 05, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.